The Brazilian version of the 25-Item National Eye Institute Visual Function Questionnaire: translation, reliability and validity

PURPOSE: To develop and investigate the reliability and validity of a Brazilian version of the 25-Item National Eye Institute Visual Function Questionnaire. METHODS: A Brazilian version of the questionnaire was developed and applied to patients with chronic eye diseases and healthy controls. Reliability was assessed by Cronbach's alpha coefficient, intraclass correlation coefficient and interrater reliability coefficient. Participants were submitted to the Medical Outcomes Study Short Form-36 Questionnaire. Validity was estimated by the correlation between the questionnaires and among the 12 subscales of the questionnaire, subscales scores and visual acuity, patients' and controls' subscales scores, and the factor analysis. Responsiveness of the questionnaire was assessed in a group of patients before and following cataract surgery. RESULTS: Cronbach's alpha, intraclass correlation and interrater reliability coefficients were highly significant. Validity was well established in all tests. In patients who underwent cataract surgery, a better vision-related quality of life was observed following surgery. CONCLUSION: The Brazilian version of the 25-Item National Eye Institute Visual Function Questionnaire has valid and reliable psychometric properties and can be applied to vision-related quality of life research.(AU) OBJETIVO: Desenvolver e investigar a confiabilidade e a validade da versao brasileira do Questionario de Funcao Visual de 25 Itens do National Eye Institute. METODOS: A versao brasileira do questionario foi desenvolvida e aplicada em pacientes com doencas oculares cronicas e controles sadios. A confiabilidade foi calculada pelo coeficiente alfa de Cronbach de correlacao intraclasse e de confiabilidade entre examinadores. Foi usado o questionario "The Medical Outcomes Study Short Form-36". A validade foi calculada pela correlacao entre as escalas dos questionarios e entre as 12 subescalas do questionario, a pontuacao das subescalas e a acuidade visual, a pontuacao das subescalas de pacientes e controles e a analise fatorial. A validacao do questionario foi calculada em grupo de pacientes antes e apos cirurgia de catarata. RESULTADOS: O coeficiente de alfa de Cronbach, de correlacao intraclasse e de variacao entre entrevistadores, e os testes de validade da versao brasileira foram significantes. A responsividade foi confirmada pela melhora na qualidade de vida visual no grupo submetido a cirurgia de catarata. CONCLUSAO: A versao brasileira do Questionario de Funcao Visual de 25 Itens apresenta propriedades psicometricas validas e confiaveis e pode ser aplicado em pesquisa de qualidade de vida visual.(AU)